This invention relates to fully automated bag handling and filling machines which pick up bags one at a time from a supply source, fill the bags, and release them in an integrated, high speed, and efficient system. More particularly, this invention is drawn to an apparatus for bottom filling bags used in combination with a bag sealing apparatus that is capable of closing and handling both paper and plastic type bags within a fully automated bag handling and filling machine.
Automated bag handling and filling machines are known in the art. See, for example, U.S. Pat. Nos. 4,322,932, 4,432,186, and 4,612,965 issued to Harold R. McGregor. Traditionally, bag handling and filling machines have utilized bag holding clamps on a clam shell type of filling spout to hold the bag during a filling operation on the spout, with the filled bag then being conveyed to a separate, closing machine for closing the bag top, as by stitching or by heat sealing. Bag control and forming bars have been incorporated to grip the bag mouth, after filling, and to lower it onto a conveyor, which serves to transport the filled to a separate, bag closing station. Such bag handling and control bars are shown, for example, in U.S. Pat. No. 4,322,932. Recognizing that operating efficiencies including more compact machine footprints and reduced operational costs could be realized by incorporating the bag sealing function within a single machine for handling, filling, and sealing bags, such integrated machines have been developed. For an example of such an integrated machine see U.S. Pat. No. 5,771,667 issued to Harold R. McGregor.
However, bag sealing apparatuses for such integrated bag handling and filling machines have been limited in the manner in which bags could be filled and to closing only plastic bags. Consequently, a bottom filling apparatus for filling bags from the bottom up and a bag sealing apparatus capable of handling and closing both plastic bags and paper bags have been developed.
A first objective of this invention is to provide a filling mechanism that allows a bag to be filled from the bottom up. Another objective of this invention is to provide a bag sealing apparatus which is capable of handling and closing both plastic and paper bags. Yet another objective of this invention is to provide an integrated bag filling machine which is capable of both filling, sealing, and handling bags and which occupies a minimum of space on a factory floor. A further objective of this invention is to provide a bag closing apparatus capable of handling and closing both plastic and paper bags and which may be mounted in a number of ways, including on a vertically moveable carriage or from an overhead support structure.
The present invention overcomes the problems of the prior art by utilizing a tube-type of bottom filling device in combination with a bag sealing apparatus locate within the same lateral confines as the filling device and bag hanging spout. The bag sealing apparatus is mounted on a vertically moveable carriage positioned in substantial vertical alignment with the filling device. The tube-type of bag filling device may comprise either a slip tube or a vertical auger contained within a fill tube.
The bag sealing apparatus of the present invention comprises a pair of opposable forming bars and a pair of independently actuable and opposable sealing bars which are disposed between a pair of parallel mounting plates in such a manner that the forming bars clamp the top of a filled bag below said sealing bars.
The forming bars are essentially an apparatus for clamping and holding a bag that is to be sealed. In order improve the grasping capabilities of the forming bars, the respective bars may be provided with complementary contoured faces that are arranged and constructed to securely clamp the top of a filled bag therebetween. One such face structure includes arranging the complementary contoured faces of the clamping or forming bars in a tongue-in-groove pattern. Furthermore, in order to ensure the secure clamping of a bag between the forming bars of the present invention, the forming bars are constrained to pivot between the mounting plates in symmetrical opposition with one another.
To close and seal the tops of paper bags, a first of the sealing bars of the bag sealing apparatus may include a bag folding arm for folding a bag top over into contact with a side of the bag being sealed. The bag folding arm or fold-over arm is pivotally mounted to one of the sealing bars. The fold over arm works in conjunction with a bag crimping structure arranged and constructed to form a crimp in the top of said filled bag so as to bias the top of said filled bag in a desired fold direction. The bag crimping structure of the bag sealing apparatus comprises respective forming surfaces formed in the opposable faces of the sealing bars. The forming surfaces of the sealing bars are arranged to clamp a bag top therebetween and form a crimp in the bag top to bias the top of the bag in a desired fold direction.
In addition, one of the sealing bars has secured thereto a backing mechanism which may be a simple plate arranged to oppose the compressive forces exerted by the fold-over arm mounted on the sealing bar. The compressive forces exerted between the compression plate of the backing mechanism and the fold over arm folds the top of a bag over into contact with the side of the bag and permits the heat sensitive adhesive to seal the bag top closed. One embodiment of the backing mechanism comprises a plurality of compression rollers arranged to be reciprocated laterally with respect to the fold over arm when the fold over arm has been actuated to fold the bag top over into contact with the bag side.
It may also be desirable to provide a heating element on the forming surfaces of the sealing bars to heat the bag top at the point of contact between the forming surfaces and the bag top. This application of heat to the bag top is intended to seal a plastic bag or the plastic liner of a paper bag. In addition, the forming or clamping bars may be provided with heating elements that also allow the forming bars to seal a plastic bag or the plastic liner of a paper bag.
One manner of sealing a paper bag top closed is to utilize a heat sensitive adhesive. Therefore, a heating element is may be secured to one of the sealing bars so as to activate the heat sensitive adhesive applied to a bag side. The folding arm secured to one of the sealing bars may then fold the bag top into contact with the side wall of the bag so as to seal the bag top with the activated heat sensitive adhesive.
The bag sealing apparatus of the present invention is intended to be used in conjunction with a bag filling machine and therefore it is desirable that the mounting plates between which the sealing bars and the forming or clamping bars are disposed be vertically movable between a first, inoperative position, and a second, operative position in which the sealing bars and the forming or clamping bars may engage the top of a filled bag.
Alternatively, it is possible to alter the structure of the bag sealing apparatus so that it may be laterally moveable side-to-side or front-to-back between its first and second positions, as opposed to the preferred vertical movement.
The above described bag sealing apparatus is may be used in conjunction with a bag filling mechanism that comprises a material dispensing spout having clamping members thereon for maintaining a bag on the spout, and a slip tube suspended in substantially vertical alignment with the spout.
The material dispensing spout has a discharge end defined by closure members that are operable between closed and open positions for discharging particulate material into a bag and has a power actuator arranged to open and close the spout discharge end closure members. Clamping members on the spout discharge end are movable between a closed position in which the members are in clamping engagement with the mouth of a bag that is placed on the spout discharge end and an open position in which the members may release or receive a bag mouth from the spout discharge end. The slip tube is suspended in substantially vertical alignment with the spout and is vertically moveable between a first, bag filling position in which the slip tube extends through the spout discharge end and into a bag to be filled when the spout is open and a second, inoperative position in which the slip tube is retracted vertically and the spout is closed. The bag sealing apparatus described above is movable in a travel path between a first, bag receiving position in close proximity to the spout discharge end and a second, bag discharge position away from the spout.
It is specifically intended that the travel path of the bag sealing apparatus not be limited to vertical movement only, and may move from side-to-side or from front-to-back as indicated by the directional arrows in FIG. 11.
In order to facilitate the settling of the material with which a bag is filled, a nozzle may be provided within the slip tube. The nozzle is connected to a vacuum pump for evacuating air from the headspace of the bag being filled. The air in the headspace of the bag is preferably removed immediately prior to the closing of the material dispensing spout.
In the preferred embodiment of the present invention, the bag sealing mechanism is provided with a pair of sealing bars that are arranged and constructed to rotate between a first position in which these sealing bars are clear of the path of rotation of the crimping bars, and a second position in which the sealing bars engage the bag gripped by the forming bars to seal the inner liner of the bag.
The sealing bar mechanisms of the present invention comprise a sealing bar that is rotatively mounted upon a pair of U-shaped members or legs. Each of the U-shaped members upon is connected, as by bearings, between the legs of a respective forming bar assembly. A cam bearing projects inwardly from each of the U-shaped leg members to facilitate the rotation of the sealing bars between their first, inoperative positions and their second, operative positions. A pair of cam plates is mounted to the inner surface of the respective parallel side plates upon respective power cylinders. The power cylinders move the cam plates between first, lower positions and second, upper positions. The first and second positions of the cam plates correspond to the aforementioned first, inoperative position and second, inoperative position of the sealing bars themselves. To rotate the sealing bars, cam plates have formed therein cam follower slots which face outwardly toward the respective parallel side plates. The cam follower slots are arranged such that when the forming bars are rotated inwardly to grip and support a bag, the cam follower slots in each of the cam plates will receive the cam bearings of the U-shaped members adjacent to the parallel side plate to which the respective cam plates are mounted. When the cam plates are moved upwardly to their second position, the sealing bars are thereby caused to rotate to there second, operative position due the interaction of the cam bearings of the U-shaped members and the cam follower slots of the cam plates.
In order to seal a bag gripped by the forming bars of the present invention, one of the crimping bars is provided with a fold-over bar that is constructed and arranged to rotate between a first, upper position and a second, lower position. In its first, upper position, the fold-over bar is clear of the bag. As the fold-over bar rotates to its second, lower position, the fold-over bar folds a portion of the bag above the transverse crease formed by the crimping bars against a portion of the bag that is below the transverse crease. The fold-over arm achieves a mechanical advantage in the folding process by rotating between the first and second positions along a complex curvilinear path.
These and other objectives and advantages of the invention will appear more fully from the following description, made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views.